Optical transceivers are the backbone of optical networks. Optical transceivers transmit and receive the application critical data in network implementations. Such transceivers are commonly placed in direct communication with one another via a fiber optic coupling so that data may be shared between transceivers and thus shared between different nodes and devices of the network.
To bring uniformity to optical transceiver configurations, a number of industry wide standards have been developed. One such standard is the Small Form Factor (SFF) Transceiver Multisource Agreement that has been developed to establish internationally compatible standards for systems including Asynchronous Transfer Mode (ATM), FDDI, Fibre Channel, Fast Ethernet, Gigabit Ethernet, and Synchronous Optical Networking (SONET)/Synchronous Digital Hierarchy (SDH) applications. The SFF standard sets packaging outlines, circuit board layout, and pin function definitions for compliant transceivers. Optical transceivers compliant with the SFF package protocol may be designed to have a ten pin input/output stage, for example, where every pin of the stage is dedicated to a particular purpose. While this uniformity brings obvious advantages, there are attendant disadvantages. In particular, the SFF packaging standard limits the physical dimensions of an optical transceiver, which limits designers from being able to add additional functionality to a device. The SFF packaging standard, for example, limits the availability of designers to use compliant optical transceivers for purposes that would require additional electrical inputs, due to the pin limitation.
Standards such as the SFF standard have limited designers from being able to effectively use built-in test functionality or other health information techniques to gather and report operational data on an optical transceiver. For example, when there are performance problems on an optical network, it is desirable for designers or test engineers to ascertain which component is causing signal loss so that the component may be isolated and replaced without substantial downtime and without substantial replacement costs. Currently, a technician would be required to break the optical network and insert a separate analyzer along different portions of the network to eventually isolate the fault condition and equipment. It is therefore desirable to have self-examining optical transceivers capable of internally detecting faults, for example, faults between two transceivers spaced apart by an optical fiber, and report that diagnostic data back to a microcontroller for analysis.
With optical transceivers limited by space constraints like those of the SFF standard, designers have been unable to devise a technique for effectively communicating diagnostic data from the transceiver as the pins on the transceiver have already been assigned different roles. In essence, there are not enough input/output pins to have the optical transceiver output yet another signal, i.e., a detailed diagnostic or health information.
It is therefore desirable to have a technique for communicating with an optical transceiver to provide diagnostic and/or other transceiver specific data within the current SFF packaging framework.